D rafting-instrument



(No Model.)

T. TOSTEVIN.

DRAFTING INSTRUMENT.

Patented Apr. 4, 1893.

THE raonms mans a), Moro-Luau" vuwmcncu o v;

UNITED STATES PATENT OFFICE.

THOMAS TOSTEVIN, OF COUN GIL BLUFFS, IOW'A.

DRAFTlNG-INSTRUMENT.

SPECIFICATION forming part of Letters Patent No. 494,944, dated April 4, 1893.

Application filed October 1, 1892.

To whom it may concern..-

Be it known that I, THOMAS Tos'rnvm, of Council Blnfisfin the countyof Pottawattamie and State of Iowa, have invented certain new and useful Improvements in Drafting-Instrue ments; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

This invention relates to drafting instruments and is especially designed as an improvement on the device shown and described in Letters-Patent No. 238,990, issued to me March 15, 1881.

The object of the invention, primarily, is to provide a square and protractor which can be readily and easily used on any drawing board or table, and by means of which a great nicety of adj ustmcnt is secured and the parts can be readily and easily operated, whereby the drafting is greatly facilitated.

The invention consists in providing a pivoted rule or straight-edge having the pro tractor scale or circle arranged thereon concentrically therewith.

The invention further consists in providing a drafting instrument with a pivoted rule or straight-edge composed of translucent material through which the operator can see the work covered by said straight edge.

The invention further consists in providing a drafting instrument with a pivoted rule or straight-edge of translucent material and having a protractor circle or scale arranged thereon concentrically therewith.

The invention further consists of a drafting instrument having a pivoted rule or straight edge and an adjustable vernier arranged concentric with the protractor scale or circle on said straight-edge.

The invention further consists of a drafting instrument having a straight-edge in engagement with a guide against one side of a groove in which said straight-edge is firmly held by spring-pressure.

The invention further comprises a drafting instrument having a separate grooved bar in which lit the webs or flanges of an adjustable guide with which latter a straight-edge engages.

The invention also comprises the detail Serial No. 447,485. (No model.)

construction, combination and arrangement of parts, substantially as hereinafter fully set forth and particularly pointed out in the claims.

In the accompanying drawings:-Figure l is a plan view illustrating my improved drafting instrument, with parts broken away. Fig. 2 is alongitudinal sectional view on the line -.r:z:, Fig. 1. Fig. 3 is a bottom plan view of the separate grooved bar. Fig. 4. is a plan view of a slightly modified form of my invention. Fig. 5 is a cross-sectional view thereof. Fig. 6 is a detail sectional view on the line y'y, Fig. 1.

Referring to the drawings, A designates a rule or straight-edge, and a. an adjustable guide of approximately T-shape in plan view. This guide has a groove orirecess a therein in which rule or straight-edge A snugly tits, the same being held by overhanging plates 0. attached to said guide. This rule or straightedge is held firm against one side-wall of said groove by spring-pressed rollers 0. These rollers are located in cut-away portions of the guide and are pivoted to the free ends of spring-plates at. These s pring-pressed rollers are concealed from view by two of the plates a From the under side of guide a project webs or flanges b.

C is a bar provided with a longitudinal V- shaped groove b in which snugly fit the webs or flanges b. This bar is made of heavy material, preferably steel, and to its under side, at periodical points, are secured pads or disks 5*, of cork or other suitable adhesive material. These pads or disks by reason of their frictional contact with the top of a drawing board or table prevent the bar from slipping. By means of this bar no specially constructed drawing board or table is required and wherever the bar is located the webs or flanges of guide a can be placed in its groove and the adj nstment or sliding of said guide and of the rule is readily and easily accomplished. By making groove b of V-shape the webs or flanges b will fit snug therein and all wabbling or shaking of the guide is prevented.

D designates a second rule or straight edge having the protractor scale or circle D'which incloses a disk like portion D The latter is pivotally mounted on the inner end of rule or straight edge A. This straight edge D has a central boss the opening d in which and in said straight-edge is beveled or inclined outwardly toward the under side of said straight edge. Through this opening is passed a stud or screw (:1 the head of which is beveled or tapered to correspond with the bevel of opening at and adjacent this bevel or taper is a squared portion d which fits snug in the square openingtof a barrel d fitted in an opening in the inner end of straight edge A. Upon the upper threaded end of stud orscrew d is a milled nut d, which, when screwed down, will firmly bind the parts together, and permit the straight edge D to turn on its bearedgeof plate 6 and thus hold the Vernier at The outer curved edge of this adjustable Vernier conany point to which adjusted.

forms to the protractor scale or circle, and

upon the upper surface of said Vernier is a scale f graduated to degrees or any part or 1 It will be seen that the vernier is mounted concentrically to the graduated sector or protractor scale, an'd hence the desired degree or fraction is readily and easily fraction thereof.

obtained.

The. straight-edge may be of any form or contour and is preferably made of sheet amber or other translucent material whereby the draftsman or operator can view the lines or work covered by said straight-edge. Another advantage of making the straight-edge of amher or translucent material is that it is exceedingly light in weight, and can be of any size.

I prefer to make this amber straight edge of approximately triangular shape, with all, or

two, of its sides of equal length. r

If desired, instead ofmaking the straightedge of one or more long sides, or of triangular shape, it can be made in theform shown in Fig. 4, in which I employ a removable rule 5 G which carries a dovetail plate g designed to fit and engage a correspondingly shaped. block or strip g attached to the under side of the circular disk D, said strip and plate being tapered throughout their lengths. This 1 removable rule or straight edge can be of any 5 desired length and hence a series of rules is generally kept close at hand ready for use.

While this form may be employed in connection with a protractor made of amber or trans- 1 lucent material, yet it is more especially de-;

signed for use in connection with metallic protractor-disks.

The operation and advantages of my invention are apparent to those skilled in the art working on a threadto which it appertains. A drafting instrument thus constructed is extremely simple and inexpensive and the same is capable of scale or circle I am enabled to secure great accuracy and nicety of adjustment to any de-' Y sired angle or inclination. Then again by making the protractor rule or straight edge of translucent material the draftsman is enabled to keep his work in view.

I claim as my invention- 1. A drafting instrumentcomprislng a rule 7 or straight edge, asA, asecond rule or straight edge having a protractor circle, a pivot-connection between said rules or straight edges,

said protractor circle being concentric to said pivot-connection,and the adjustable Vernier held by said pivot-connection, substantially as set forth.

2. The herein-described drafting instrument, comprising the rule or straight edge A having an opening therein, the rule or straight-edge D having a countersunk or beveled hole or opening and a central boss, and the pivot passed through said openings and having a beveled head fitting in said beveled hole or opening together with a binding nut, as set forth.

3. The herein-described improved drafting instrument, comprising the rule or straightedge A having a curved plate or projection,

.the barrel having an opening and a lower narrowed end, the rule or straight edge D having a central boss and beveled opening, the stud or screw having a beveled head and forming a pivot-bearing for said latter rule or straight edge, the Vernier pivoted on said narrowed end of said barrel, and the adj ustable nut carried by said Vernier for engaging said curved plate or projection, as set forth.

4. Thecombinationwith the rules or'straight edges, and a guide therefor having webs or flanges-projecting therefrom, of an independent disconnected bar having a groove in which said webs or flangesfit, and of weight sufficient to retain its position, asset forth.

5. The combination with the rulesorstraight edges, and a guide therefor having webs or flanges, of an independent disconnected bar having an upperlongitudinal V-shape groove or recessfor said webs or flanges, and provided with adhesive pads or disks on its under side, said bar being of weight sufficient to retain its position, as set forth.

6. The combination with the two rules or straight-edges, of the guide having a groove for one of said rules or straight-edges and springs holding said rule or straight edge firm in said groove, substantially as set forth.

7. The combination with the two rules or rules or straight-edges,having a groove and overhanging plates, the springplates attached to said guide and the rollers carried by the free ends of said spring-plates, substantially as and for the purpose set forth.

In testimony whereof I have signed this speoifieetion in the presence of two subscribing witnesses.

' THOMAS TOSTEVIN.

Witnesses:

J. NoTA MCGILL, WM. S. Honens. 

